mysql_num_rows not working.

[mike12255]

Im trying to figure out if a user has already downloaded something so im seeing if they have a uid (user id) in the database along with the nid (note id) that they are trying to download. I echoed out the sql and it returned this:

 

SELECT * FROM purchases WHERE uid =1 AND nid =7

 

i manually ran that sql in phpmyadmin and it returned a couple rows.  However my var $rows = mysql_num_rows($res2) has no value when i echo is out. Appriciate any help here is my code:

 

<?php
$sql2 = "SELECT * FROM purchases WHERE uid =".$user_id." AND nid =".$id;
				$res2 = mysql_query($sql2) or die (mysql_error());
				$rows = mysql_num_rows($res2);
				?>

 

[dcro2]

Are you absolutely positively sure $user_id and $id contain what you think they do? Echo $sql2 so you can see what the query actually is.

[mike12255]

i did that and i got the query that i qouted above

[mikosiko]

can you show more code?... I don't see any echo in the posted one (not saying that you don't have it)

[mike12255]

I took out the echos and die statment, but here is the full code:

 

<?php
require_once("models/config.php");

if(isUserLoggedIn())
	{
		if($id = $_GET['nid']){

		$sql = "SELECT * FROM notes WHERE id = ".$id;

		$res = mysql_query($sql) or die (mysql_error());

		while ($row = mysql_fetch_array($res)){

			$noteName = $row['noteName'];
			$name = $row['name'];
			$cost = $row['cost'];

			$user = $loggedInUser->display_username;

			$sql = "SELECT * from userCake_Users WHERE Username = '$user'";

			$res = mysql_query($sql) or die (mysql_error());

				$user_id = getInfoFromUsername($user);
				$user_id = $user_id['User_ID'];

				$sql2 = "SELECT * FROM purchases WHERE uid =".$user_id." AND nid =".$id;
				$res2 = mysql_query($sql2) or die (mysql_error());
				$rows = mysql_num_rows($res2);
				die($sql2);

			while ($row = mysql_fetch_array($res)){
				$user_id = $row['User_ID'];




				if ($rows > 0){
					header("Location:view.php?error=4");	
				}

				$userCredits = $row['credits'];
				if ($userCredits >= $cost){
					$sql = "UPDATE userCake_Users SET credits = credits -".$cost." WHERE Username ='$user'";
					$res = mysql_query($sql) or die (mysql_error());

					$date = time();
					$sql3 = "INSERT INTO `purchases` (nid,uid,`date`) VALUES('$id','$user_id','$date')";
					$res3 = mysql_query($sql3) or die (msyql_error());
					$location = $name;
					header("Location: download.php?f=".$location);



				}else{
				header("Location:view.php?error=3");	
				}

			}


		}



		}else{
			header("Location:view.php?error=2");

		}

	}else{
		header("Location:view.php?error=1");
	}


?>

 

[maxudaskin]

Try this.

<?php
$sql = "SELECT * FROM `purchases` WHERE `uid` = '$user_id' AND nid = '$id'"; // If you're using double quotes, you can leave the variables in there
$query = mysql_query($sql) or die (mysql_error());
$row_cnt = mysql_num_rows($query);

echo "The SQL query $sql returns $row_cnt rows.";

 

Put that in. I have a feeling that it is because you didn't put your single or double quotes around the values of uid and nid.

[mike12255]

problem solved thanks a lot for that.

[maxudaskin]

Was it the SQL string?

[mike12255]

not quite solved.. the echo you added says this:

The SQL query SELECT * FROM `purchases` WHERE `uid` = '1' AND nid = '7' returns 13 rows.

 

however this doesnt work it skips it:

if ($row_cnt > 0){
					header("Location:view.php?error=4");	
				}

[maxudaskin]

<?php
if ($row_cnt > 0){ // This is pretty much saying, "if there are more than zero rows, return an error"

// I assume you want it to return an error if there is less than one row?

if ($row_cnt < 1){

[mikosiko]

I see a bigger problem in your code... you are altering your resultset ($res) inside of your main loop (first while).. that could generate all kind of inconsistence...

 

and your second while

				while ($row = mysql_fetch_array($res)){
				$user_id = $row['User_ID']; 

 

seems to be using the wrong resultset and variables... and also looks out-off-place  (if validating num_rows inside the loop???)

 

 

[mike12255]

ok, ive completly rewritten the file however if the user has bought the note already it still does not redirect them to view.php?error=2 here is my code:

 

also:

 

die($row2); // returns nothing

echo ("there are a total of ".$row2. " rows"); // returns there are a total of 17 rows

 

<?php
require_once("models/config.php");

if(isUserLoggedIn())
	{
		$id = mysql_real_escape_string($_GET['nid']);
		$username = $loggedInUser->display_username;
		$user_id = getInfoFromUsername($username);
		$user_credits = $user_id['credits'];
		$user_id = $user_id['User_ID'];

		$sql = "SELECT * FROM notes WHERE id = '$id'";
		$res = mysql_query($sql) or die (mysql_error());
		$row = mysql_fetch_array($res);
		$cost = $row['cost'];
		$filename = $row['name'];

		$sql2 = "SELECT * FROM purchases WHERE nid = '$id' AND uid = '$user_id'";
		$res2 =mysql_query($sql2) or die (mysql_error());
		$row2 = mysql_num_rows($res2);

		if ($row2 > 0){
			//already bought the note
			header("Location: view.php?error=2");
		}

		if ($row['cost'] <= $user_credits){

		$new_value = $user_credits - $cost;
		$sql3 = "UPDATE userCake_Users SET credits = '$new_value' WHERE User_ID = '$user_id'";
		$res3 = mysql_query($sql3) or die (mysql_error());

		$date = time();
		$sql4 = "INSERT INTO purchases (nid,uid,`date`) VALUES ('$id','$user_id','$date')";
		$res4 = mysql_query($sql4) or die (mysql_error());
		header("Location: download.php?f=".$filename);



		}else{
			//not enough credits
			header("Location: view.php?error=3");

		}



	}else{
		//not logged in
		header("Location: view.php?error=1");

	}


?>